Silver salts of sulfur-containing aliphatic carboxylic acids as lightsensitive compounds



- United States Patent 3,330,663 SILVER SALTS 0F SULFUR-CONTAINING ALI- PHATIC CARBOXYLIC ACIDS AS LIGHT- SENSITIVE COMPOUNDS Edith Weyde and Anita von Konig, Leverkusen, Germany, assignors to Agfa-Gevaert Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Filed July 15, 1965, Ser. No. 472,308 Claims priority, application Germany, Aug. 14, 1964, A 46,854 Claims. (CI. 96-94) This invention relates to a light-sensitive photographic material which contains silver salts of sulfur-containing aliphatic carboxylic acids as light-sensitive compounds. Silver halides are used as light-sensitive compounds in conventional photographic materials. Organic silver salts, for example mercaptides, have also been proposed for this purpose, but have not been used in practice because they are not sufficiently light-sensitive or suffer from other disadvantages.

It is among the subjects of the invention to provide photographic elements, which contain silver salts of sulfur-containing aliphatic carboxylic acids as light-sensitive compounds.

We now have found that silver salts of aliphatic carboxylic acids, the aliphatic chain of which is substituted with a mercapto or organo substituted mercapto group are eminently suitable for photographic purpose. Particular exhibit compounds of the following formula:

3,330,663 Patented July 11, 1967 wherein n=1 or 2,

=alkyl, preferably with up to 18 carbon atoms, such as benzyl or phenylethyl, aryl such as phenyl or naphthyl, or heterocyclic rings such as diazolyl, oxazolyl, triazolyl, oxidiazolyl, thiadiazolyl, azaindenyl, preferably tetraor pentaazaindenyl, benzthiazo'lyl, naphthiothiazolyl, benzooxazolyl, naphthoxazolyl, pyridyl, quino-linyl, pyrimidyl, quinoxalinyl, quinazolinyl, which radicals may in turn be substituted, for example, by alkyl, preferably with up to 18 carbon atoms, aryl such as phenyl or naphthyl, hydroxyl, alkoxy with preferably up to 12 carbon atoms, aroxy such as phenoxy, acyl preferably acyl derived from aliphatic carboxylic acids having up to 18 carbon atoms, amino, alkylamino, the

alkyl groups of which having up to 5 carbon atoms, acylamino with preferably acyl groups being derived from aliphatic carboxylic acids having up to 18 carbon atoms or aryl-substituted amino preferably a phenylamino, mercapto groups, mercapto groups substituted with alkyl having up to 18 carbon atoms, a phenyl, a naphthyl or a heterocyclic radical, halogen such as chlorine or bromine, sulfo groups or carboxyl groups and the like, and

=a branched or unbranched alkylene chain having preferably up to 12 carbon atoms in particular 1-5 carbon atoms, whereby the alkylene chain can further be substituted with aryl preferably a phenyl, hydroxyl, alkoxy, halogen such as chlorine or bromine and the like. Sulfur-containing aliphatic carboxylic acids useful accord- R'(S) XCOOAg ing to the invention, include the following: 1 184 C:

N S-C H20 0 0H 2 S C H2C OOH Beilsteln, v01. 3,

| page 249. C H2 S OH2C 00H 3 H0O0-H;O-S(OH2) SCH COOH Beilstein, v01. 3, 3rd Supp. vol; part 1, page 416; 4 oonz-ongs om-c 0 011; 5 HOOC-CHZ S(CH2)3SCH2 O0OH Beilstein, vol. 3,

3rd Supp. vol: part 1, page 417. 6 H0OCOHzS(CH2)4S-CH2COOH Beilstein, v01. 3, 3rd Supp. vol. part 1, page 417. 7 HOOC'OHg-S(CH;) SCH;COOH Beilstein, vol. 3, 3rd Supp. vol. part 1, page 418: 8 0H Beilstein, v01. 3,

l page 250. OH CSCH2C O OH SCHzC O OH OH OH J. Am. Soc. 74, C 9 2 3 page 5577 (1952);

CHsCSCHz-C O OH S-OH2C O OH 10 CH, 56-59 C.

I CuH2 -CSCH2C O OH-ZHgO -CHa-O O OH Beilstein, v01. 3, l1 CEBU-S H: C 0 OH 3rd pp V0];

part 1, page 413; 12 C12H25S-CH2-COQH 56 C. 13 HOOCCH;SOH3-O O OH Beilstein, vol. 3,

page 253.

aralkyl (iTHr-COOH (FETCOOH CIHz- -COOH Beilstein, v01. 3,

page 291.

Beilstein, v01. 3,

page 291.

Beilstein, v01. 3, 3rd Supp. vol. part 1, page 511.

J. Am. Chem. Soc.

vol. 66, page 1758 (1944).

Beilstein, v01 3,

3rd Supp. vol. part 2, page 924.

Beilstein, v01. 3, 3rd Supp. v01. part 2, page 924.

Beilstein, vol. 3,

page 439.

Beilstein, v01. 12, 103-104 C.

page 485.

"'5 CHE-C0011 I COOH SCHa-COOH S-CHa-CO OH OH S-OHr-C O OH S-OHa-C O OH S-CHr-C O OH Beilstein, v01. 6,

page 313.

Beilstein, v01. 6,

page 463.

Beilstein, v01. 6,

page 463.

Beilstein, v01. 6,

page 328.

Beilstein, v01. 6,

2nd Supp. vo1., page 343.

Beilstein, v01. 6, 1st Supp. voL, page 150.

17.8. Patent 2, 897,081.

Beilstein, v01. 6, 1st Supp. v0l., page 195.

Beilstein, vol. 6,

page 337.

241 C. (decomposition) HaN SLS-CHzC O OH (ti-*S-CHr-C O OH S-CHa-COOH COOH @s-om-co OH COOH S-CHr-C O OH S-CHzCOOH C1 S-CHr-OOOH S-CHz-CO OH S-CHz-C O OH KN COOH 175 C. (decomposition) Ann. 353, page 127 J. Am. Soc. 74,

page 5577 (1952).

Beilstein, v01. 10, 2nd Supp. v01., page 73.

Beilstein, vol. 10, 2nd Supp. vo1., page 137.

Beilstein, v01. 10,

page 950.

Beilstein, vol 6,

page 62.3.

Beilsteln, v01. 22, 2nd Supp. voL, page 167.

Beilstein, vol. 22, 2nd Supp. vo1., page 302.

Beilstein, vol. 22, 2nd Supp. v01., page 164.

N Y J CHr-O 0 OH N HOOC-H ?CH:COOH T Beilstein, v01. 23,

1st Supp. voL, page 119.

Beilstein, vol. 25,

page 62.

Beilstein, v01. 25,

page 15.

270 0. (decomposition) 230340 (decom- TS-CHPC 0 011 \N/ s-om-ooon S-CHz-COOH S-OHr-COOH G s-cm-c 0 OH -S-CHr-CO OH 269' O. (decomposition) 205 0. (decomposition) 170 C. (decomposition) (1.5. Patent 2,819,965.

302 0. (decomposition) Beilstein, vol. 27,

270 0. (decomposition) Beilstein, v01. 23,

2nd Supp. VOL, page 321.

N O- N 296 C. (decomposition) 300" O. (decomposition) Beilstein, vol. 26, 1st Supp. vo1., page 82.

Beilstein, v01. 26,

1st Supp. 'v01., page 169.

Beilstein, vol. 27, 2nd Supp. vol., page 787.

Beilstein, v01. 27,

1st Supp. v0l., page 612.

Uncrystallized 321010-51; s-cm-ooon /CHr-CH2CHr-O O OH S-CHaCHa-COOH Beilstein, v01. 3,

page 312.

Beilstein, v01. 6,

2nd Supp. voL, page 293.

Beilstein, vol. 6,

2nd Supp. v01., page 298.

260 C. (decomposition) OzNO OzN

Beflstein: vol 16,

2nd Supp. voL, page 306.

Bei1stein,vo1. 6,

2nd Supp. vol., page 313.

Uncrystallized NHi CH3 S-(BHCH2-COOH CH; S-CHCH:COOH

H00 C--TE[aCHzC-S' Sis-CHH-CIHf-C OOH 126 @Ifls s-oHr-cm-ooorr T S JSCHrCHrCH:-COOH (kHz-S- SJ-S-CHaC O OH I O OH CHFOOOH Gi -Q S (B O OH H-COOH Hl-COOH Q-e- Q 0 OH S Hr-C O OH 132 CHr-N C-s-C H 0 O H CHr-N 8 (SEC 0 OH C IIEHCOOH 8 (J O OH HzCOOH (E O OH HO O OH CHzCOOH J. Am. Soc. 74,

Page 3886 (1952).

21 103 to 113. The compounds can be isolated in the form of free acids or as alkali metal salts. The compounds can be purified by recrystallisation from or by solution and reprecipitation from water or alcohol. This is more fully described in the following examples:

PREPARATION OF s-[2-nOCTYLTHIO 1,3,4 THIADIA- ZOLYL-()]-THIOGLYCOLLIC ACID-COMPOUND 96 PREPARATION OF THE SODIUM SALT CF S-[2-n-BUTYL- THIO-1,3,4-THIAZOLYL-(5) ]-THIOGLY'COLLIC ACID COMPOUND '93 103 g. /2 mol) of Z-n-butylmercapto-S-mercapto-thiadiazole-(1,3,4) are dissolved in 800 ml. of a 2.5% by weight sodium hydroxide solution and, after the addition of 63 g. of monochloroacetic acid, the solution is heated for 15 minutes on a steam bath while stirring. 50 g. of soda are then added in portions at about 60 C., after which the solution is heated for 3 hours on a steam bath and after cooling the product is precipitated by acidification with 50% aqueous acetic acid. The crude product is purified by washing with water. The resulting 65 g. of crude product are dissolved in an equivalent quantity of 5% aqueous soda solution, after which the sodium salt of the product is isolated in the form of fine needles by concentration. The salt melts at 218 C. after washing with acetone and drying in vacuo.

Compounds 129-135 are prepared by reacting a Schilf base with a mercapto-substituted aliphatic carboxylic acid as described for example by Stacy et al., J.A.C.S. 77, 3869, 1955.

The preparation of conventional silver halide emulsion involves three separate steps: (1) precipitation of the silver halide in the presence of a protective colloid preferably gelatin and physical or Ostwald ripening, (2) flocculation and freeing of the emulsion of excess water-soluble salts, and (3) the chemical or after-ripening to obtain increased speed and sensitivity (compare Mees The Theory of the Photographic Process).

The novel photographic emulsions of the present invention can be prepared in analogous manner.

The silver salts are prepared from equimolar quantities of the thioaliphatic carboxylic acid and the soluble salt such as silver nitrate. The reaction takes place in an aqueous solution of the reaction components, preferably in the presence of a protective colloid such as gelatin, polyvinyl alcohol, or sodium alginate. Depending on the type of thioaliphatic carboxylic acid used, the components are forming binding agent reacted in a molar ratio about 1:1. That molar ratio relates to the number of carboxyl groups. Thus an acid Which contains two carboxyl groups is preferably reacted with 2 mols of water-soluble silver salt such as silver nitrate. Acids which contain 3 or more oarboxyl groups are preferably reacted with a least 2 mols of silver salt. The most effective and suitable molar ratio will be apparent to those skilled in the art upon making the ordinary tests and observations customarily used in the :art of emulsion making. It has been found that an excess of water soluble silver salt produces fogging in the photographic emulsion. On the other hand, an excess of thioaliphatic carboxylic acid up to about 10 mol percent reduce the fog level without affecting sensitivity. A higher excess of the thioaliphatic carboxylic acid is not desirable since the lightsensitivity of the silver salts of the said acid is considerably reduced.

Precipitation of the silver salt in the presence of a filmproduces an emulsion suitable for coating.

Water soluble organic as silver complexes may thioaliphatic carboxylic salts used to prepare the vention may itself for example, as a quired pH-value.

The silver salts according to the invention may also be employed in admixture with one another or with conventional silver halides.

and inorganic silver salts as well be used for the reaction with the acid. The anion of the silver silver salts according to the inbe used in the photographic emulsion, hardening agent for adjusting the rereplaced by other film-forming natural or synthetic materrals such as proteins for instance albumin or casein, algimc acids or derivatives thereof by alkali salts of alginic acid, esters of alginic acids in particular esters with lower atoms, caraghenates, polyvinylalcohol, partially saponified polyvrnylacetate, polyvinyl pyrrolidone and the like.

si-ons can also be sensitized with by R. Koslowsky, Z. wiss. photo.

The emulsion the US. Patent No. 1,574,944, polyethylene oxides and the like.

The emulsion can also be optically sensitized with the The emulsions may be hardened by any suitable hardener, such as formaldehyde, halogen substituted aliphatic acids such as mucobromic acid.

Example I 30 ml. of a 40% aqueous citric acid solution and 20 g. of diethyldisulfide-1,2,1',2-tetracarboxylic acid (comequimolar quantity of aqueous sodium hydroxide solution, are added to 1 litre of an 8% C. ml. of a 10% C. After the addition of a wetting agent, for example 5 ml.

23 the material may be developed, fixed and treated with water in the usual way. The following developer mixture is used:

G. p-Methylaminophenol 1 Anhydrous sodium sulfite 13 Hydroquinone 3 Anhydrous soda 26 and Potassium bromide, disolved in 1 litre of water 1 Since the silver salt precipitates in a very fine-grained form, these emulsions may be prepared with a comparably low silver content without reducing the density of the resulting images. Instead of diethyldisulfide-1,2,1,2'- tetracarboxylic acid, it is also possible to employ the following compounds in the quantities indicated:

20 g. of s-[6-methylpyrimidyl-(2,4)]-bis-thioglycol1ic acid (compound 63) 22 g. of s-[7-sulfo-naphtho-2',3: 4,5-oxazolyl-(2)]-thioglycollic acid (compound 82) 21 g. of s-[7 sulfo -chloro-benzoxazolyl-(2)]-tl1ioglycollic acid (compound 74) 27 g. of s-[2-n-dodecylthio-1,3,4- thiadiazolyl-(S)]-thioglycollic acid (compound 98) 17 g. of s-[2 anilino 1,3,4 thiadiazolyl-(S) ]-thioglycollic acid (compound 103).

Example 2 30 ml. of a 40% aqueous solution of citric acid are added to 1 litre of an 8% aqueous gelatin solution, and the solution is heated to 45 C. 20 g. of carboxymethylmercaptosuccinic acid (compound 18) dissolved in an equimolar quantity of aqueous sodium hydroxide solution are added, after which precipitation is carried out while stirring vigorously with 100 ml. of a 10% aqueous silver nitrate solution. Before coating, 3 ml. of a 1% alcoholic solution of 1-phenyl-S-mercaptotetrazole, 5 ml. of a 1% alcoholic solution of benzotriazole, 1 ml. of a 30% aqueous formaldehyde solution and 5 ml. of 30% aqueous solution of saponin are added. The emulsion is applied in known manner on to a sheet of paper and is then dried.

Since the silver salt dissolves readily in an alkaline sulfite solution, this material may be employed as lightsensitive photographic material in the silver salt diffusion process without applying a silver salt solvent such as sodium thiosulfate.

The exposed element is developeld in the usual way using thiosulfate-free transfer materials, containing development nuclei and thiosulfate-free aqueous developers. The materials are processed in accordance with common practice. After the materials have been separated, an excellent copy of the original is obtained in the transfer material.

Example 3 2 ml. of a 40% aqueous solution of citric acid are added to 1 litre of an 8% aqueous gelatin solution, and the solution is heated to 40 C. 22 g. of s-[2-n-octylthio- 1,3,4-thiadiazolyl-(5)]thioglycollic acid (compound 96), dissolved in an equimolar quantity of an aqueous sodium hydroxide solution, are then added, after which precipitation is carried out while stirring vigorously with 100 ml. of a 10% aqueous solution of silver nitrate. Before coating, 125 g. of crystalline sodium acetate, 5 g. of potassium metabisulfate, 5 g. sodium 4-diethylaminobenzene-aminomethane sulfonate-(1) and 5 ml. of a 30% aqueous solution of saponin, are added. The emulsion is cast in known manner on to a sheet of paper and dried After exposure, the material may be developed under heat or used as light-sensitive material for a developer sublimation process, for example as described in German patent specification No. 1,159,758.

Example 4 30 ml. of a 40% aqueous solution of citric acid and 18 g. of compound 126 dissolved in water which, if desired,

can be mixed with a small amount of aqueous sodium hydroxide solution to facilitate solution, are added at 40 C. to 1 litre of an 8% by weight aqueous gelatin solution. ml. of a 10% aqueous solution of silver nitrate are then added with vigorous stirring and digested for a few minutes at 40 C. After the addition of a wetting agent, for example 5 ml. of 30% by weight aqueous solution of saponin, and a hardening agent, for example 1 ml. of a 30% by weight formaldehyde solution, the emulsion is applied in known manner into a sheet of paper or into a transparent support for example of polyethylene terephthalate and dried. The sensitivity of the coated material is similar to that of conventional photographic silver chloride contact-copying papers. After exposure, the material may be developed, fixed and treated with water in the usual way. For example the developer composition referred to an Example 1 can be used. Since the silver salt is precipitated in a very fine-grain form, these emulsions can be prepared which have a low silver content as compared with a conventional silver halide emulsion without affecting the density of the final images. Instead of compound 126, it is also possible to employ the following compounds in the quantities indicated: 14 g. of compound 111; 13 g. of compound 121; 21 g. of compound 16 g. of compound 124 or 16 g. of compound 119.

Example 5 30 ml. of a 40% aqueous solution of citric acid are added to 1 litre of an 8% by weight aqueous gelatin solution, and the solution is heated to 45 C. 15 g. of compound 109 dissolved in water mixed with a little aqueous sodium hydroxide solution are then added, after which precipitation is carried out while stirring vigorously with 100 ml. of a 10% by weight aqueous solution of silver nitrate. Before casting, 3 ml. of a 1% by weight alcoholic solution of 1-phenyl-5-mercaptotetrazole, 5 ml. of a 1% by weight alcoholic solution of benztriazole, 1 ml. of a 30% by weight formaldehyde solution and 5 ml. of a 30% aqueous solution of saponin are added. The emulsion is applied to a sheet of paper in known manner and dried.

The material is exposed and further processed in accordance with the silver salt diffusion process by developing the exposed light-sensitive layer, while in contact with a transfer sheet containing development nuclei and separating the sheets when the transfer of the silver salt is completed. Since the silver salt dissolves readily in an alkaline sulfite solution, it is not necessary to apply a silver salt solvent such as sodium thiosulfate in the developer bath or in the transfer sheet. An excellent copy of the original is obtained.

Example 6 2 ml. of a 40% aqueous solution of citric acid are added to 1 litre of an 8% by weight aqueous gelatine solution, and the solution is heated to 40% C. 15 g. of compound 118 dissolved in water mixed with a small amount of sodium hydroxide solution are then added, after which precipitation is completed while stirring vigorously with 100 ml. of a 10% by weight aqueous silver nitrate solution. Before casting, 125 g. of crystalline sodium acetate, 5 g. of potassium metabisulfite, 5 g. of sodium 4-diethylaminobenzene-l-aminomethane sulfonate and 5 ml. of a 30% aqueous solution of saponin, are added. The solution is applied to a sheet of paper and dried.

After exposure, the material can be developed under heat, or used as a light-sensitive material for a developer sublimation process as described for example in German patent specification No. 1,159,758.

We claim:

1. A light-sensitive photographic element having at 2. A light-sensitive photographic element as defined in claim 1, wherein the light-sensitive silver salt is a salt having the following formula wherein R represents a member of the group consisting of alkyl having up to 18 carbon atoms, aralkyl, a radical of the benzene series, a radical of the naphthalene series and a heterocyclic ring; and

X represents an alkylene radical having up to 5 carbon atoms.

3. A light-sensitive photographic element as defined in claim 1, wherein the water-permeable binding agent of the light-sensitive layer consists essentially of at least one member of the group consisting of gelatine, albumin, alginic acid, alkali salts of alginic acid, esters of alginic acid, alginic acid amide, polyvinylalcohol, partially hydrolyzed polyvinylacetate, polyvinylpyrrolidone, starch, carboxyalkylcellulose and alkycellul ose.

4. A light-sensitive photographic element as defined in claim 1, wherein the light-sensitive silver salt emulsion layer has a pH between 1 and 6.

5. A light-sensitive photographic element as defined in claim 2, wherein X is a methylene group.

6. A light-sensitive photographic element as defined in claim 2, wherein the light-sensitive silver salt is a salt of an alkylene-bis-thioglycollic acid.

7. A light-sensitive photographic element as defined in claim 2, wherein the light-sensitive silver salt is a salt of an S-carboxyalkyl-thioglycollic acid.

8. A light-sensitive photographic element as defined in claim 2, wherein R is a heterocyclic radical of the group consisting of a quinolyl, a pyrimidyl, a quinoxalyl, quinazolyl, phthalazyl, triazolyl and thiazolyl.

9. A light-sensitive photographic element as defined in claim 2, wherein R is a methyl group which is substituted with a phenyl group and a phenylamino group.

10. A light-sensitive photographic element as defined in claim 1, and in which the light-sensitive silver salt is a silver salt of:

No references cited.

NORMAN G. TORCHIN, Primary Examiner. C. E. DAVIS, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,330,663 July 11, 1967 Edith Weyde et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 11, for the lower portion of formula 77 reading "N" read S column 13, for the left-hand portion of formula 92 reading "H C read H. C column 19, for the lower portion of formula 132 reading "-N" read NH column 20 line '70 for "processess" read processes column 21, line 20, for "THIAZOLYL" read THIADIAZOLYL column 22, line 23, for "carboxylalkylcellulose" read carboxyalkylcellulose colun 23, line 10, for "disolved" read dissolved column 25, lir

20, for "alkycellulose" read alkylcellulose Signed and sealed this 17th day of September 1968. (SEAL) Attest:

Edward M. Fletcher, Jr. EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. A LIGHT-SENSITIVE PHOTOGRAPHIC ELEMENT HAVING AT LEAST ONE LIGHT-SENSITIVE SILVER SALT EMULSION LAYER IN WHICH THE ESSENTIAL LIGHT-SENSITIVE SILVER SALT IS A SILVER SALT OF AN ALIPHATIC CARBOXYLIC ACID THE ALIPHATIC CHAIN OF WHICH IS SUBSTITUTED WITH AN ORGANO SUBSTITUTED MERCAPTO GROUP. 